Wowowow!! Max I've gotten is $18, and it was a one-time occasion. The maximum I get nowadays is $4 for certain Steemians who are a bit generous, and those are very rare. But yeah, the easiest and fastest way is just commenting. It doesn't require much investment.
However, if you're consistent like me, after 4 months you can start earning a bit on your posts. I'm getting around $2.4 in organic votes per post on top of the bid bots I use, so it's very affordable to keep posting once or twice a day to get those.
The key is being consistent and using multiple strategies at the same time. I leave comments, post, use bots, use busy, etc., and every grain of sand builds your SP up, the way it has done for you and me.